Yes and No.
You'll be able to reinstall the factory vista indeed since modding does nothing to the harddisk data, but it will not be activated right after the installation since the old SLIC(2.0) should be replaced by new SLIC(2.1) after modding. And there's no HP2.1 SLIC that is compatible with the old cert on Vista factory.

However, you may flash with an original BIOS before installing the factory Vista, which will return you the old (2.0)SLIC that is compatible with your factory Vista. Or after the installation, install the new cert(2.1) like what you do on 7 and your factory Vista should be activated.